copper

Introduction

copper, metallic chemical element; symbol Cu [Lat. cuprum = copper]; at. no. 29; at. wt. 63.546; m.p. 1,083.4°C; b.p. 2,567°C; sp. gr. 8.96 at 20°C; valence +1 or +2. Copper and some of its alloys have been used by humanity since the Bronze Age. One of the first metals known to humans, copper was smelted as long ago as c. 5000 B.C. Cyprus, from which the metal's name originally comes, was a major source of copper in the ancient world.